I don’t get the analogy. Can someone explain? How do you spend only 1.25 time and 1.5 energy to do the equivalent “work” of 4 “visits”? Not seeing the connectio

I don’t get the analogy. Can someone explain? How do you spend only 1.25 time and 1.5 energy to do the equivalent “work” of 4 “visits”? Not seeing the connection to computer arch and speculative execution.